add boost on mac

macx64/include/boost/histogram/axis/interval_view.hpp

@@ -0,0 +1,54 @@
+// Copyright 2015-2019 Hans Dembinski
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt
+// or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_HISTOGRAM_AXIS_INTERVAL_VIEW_HPP
+#define BOOST_HISTOGRAM_AXIS_INTERVAL_VIEW_HPP
+
+namespace boost {
+namespace histogram {
+namespace axis {
+
+/**
+  Lightweight bin view.
+
+  Represents the current bin interval.
+*/
+template <typename Axis>
+class interval_view {
+public:
+  interval_view(const Axis& axis, int idx) : axis_(axis), idx_(idx) {}
+  // avoid viewing a temporary that goes out of scope
+  interval_view(Axis&& axis, int idx) = delete;
+
+  /// Return lower edge of bin.
+  decltype(auto) lower() const noexcept { return axis_.value(idx_); }
+  /// Return upper edge of bin.
+  decltype(auto) upper() const noexcept { return axis_.value(idx_ + 1); }
+  /// Return center of bin.
+  decltype(auto) center() const noexcept { return axis_.value(idx_ + 0.5); }
+  /// Return width of bin.
+  decltype(auto) width() const noexcept { return upper() - lower(); }
+
+  template <typename BinType>
+  bool operator==(const BinType& rhs) const noexcept {
+    return lower() == rhs.lower() && upper() == rhs.upper();
+  }
+
+  template <typename BinType>
+  bool operator!=(const BinType& rhs) const noexcept {
+    return !operator==(rhs);
+  }
+
+private:
+  const Axis& axis_;
+  const int idx_;
+};
+
+} // namespace axis
+} // namespace histogram
+} // namespace boost
+
+#endif